1. Field of the Invention
The present invention relates generally to a Channel State Information (CSI) transmission and reception method and apparatus and, in particular, to a method and apparatus for transmitting and receiving CSI in a wireless communication system using a plurality of antennas.
2. Description of the Related Art
A Reference Signal (RS) is used in measuring a channel state or quality, such as signal strength and distortion, interference strength, and Gaussian noise, between a Base Station (BS) and User Equipments (UEs) (or terminals) and demodulating and decoding a received data symbol in a wireless mobile communication system. The RS is also used to measure a radio channel state. For example, a receiver measures a strength of an RS transmitted by a transmitter at a predetermined transmit power in order to determine a radio channel state between the receiver and the transmitter. Thereafter, the receiver requests a data rate from the transmitter, based on the determined radio channel state.
The 3rd generation evolved mobile communication standards, such as the 3rd Generation Partnership Project Long Term Evolution-Advanced (3GPP LTE-A) and Institute of Electrical and Electronics Engineers (IEEE) 802.16m, have adopted multi-carrier multiple access techniques such as Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA).
In a multi-carrier multiple access-based wireless mobile communication system, channel estimation and measurement performance is influenced by the number of symbols and number of subcarriers to which an RS is mapped on a time-frequency resource grid. The channel estimation and measurement performance is also influenced by the power allocated for the RS transmission. Accordingly, by allocating more radio resources (including time, frequency, and power), it is possible to improve channel estimation and measurement performance, thereby improving received data symbol demodulation and decoding performance and channel state measurement accuracy.
In a resource-constrained mobile communication system, however, if a radio resource is allocated for transmitting RSs, this reduces the available resources for data signal transmission. Accordingly, an amount of resources for RS transmission should be determined appropriately, by taking the system throughput into account.